Aroma
Diffusive, fresh-gassy, herbaceous odor. The gassy notes are more predominant in
poorer grades of Allo-ocimene, almost imperceptible in good grade matl. Useful in low-cost fragrances for industrial purposes, and in general as a lifting topnote, modifier for Limonene, etc. cheaper than Ocimene.
Chemical Properties
Clear, almost colorless liquid. Polymerizes and oxidizes readily. Combustible.
Uses
Component of varnishes and a variety of polymers; fragrance.
Definition
ChEBI: (4E,6E)-2,6-dimethylocta-2,4,6-triene is an ocimene that consists of octa-2,4,6-triene bearing methyl substituents at positions 2 and 6 (the 4E,6E-isomer). It has a role as a semiochemical.
General Description
2,6-Dimethyl-2,4,6-octatriene (allo-ocimene) is one of the major constituents of
Fissistigma maclurei Merr. It was identified in Alphanso mangoes using GC-MS.
Synthesis
Ocimene is produced by the flash pyrolysis or
photochemical isomerization of a-pinene.
Solubility in organics
Colorless mobile liquid. Soluble in alcohol (when fresh and unpolymerized), poorly soluble when polymerized. Insoluble in water. Miscible with essential oils and perfume chemicals.
Purification Methods
Fractionally distil allocimene through an efficient column and repeatedly distil it at 15mm through a long column of glass helices, with a final distillation from sodium under nitrogen. It should be stabilised with ca 0.1% of hydroquinone. UV: max nm( 1cm-1) 290 (32 500), 279 (41 900) and 278 (42,870). [Alder et al. Justus Liebigs Ann Chem 609 1 1957, O’Connor & Goldblatt Anal Chem 26 1726 1954, Beilstein 1 IV 1106.]
